The invention relates generally to system and method of reducing emissions and more particularly to a system and method for reducing mono-nitrogen oxides (NOx) emissions.
Typically, various combustion sources such as locomotives, vehicles, power plants, and the like, has resulted in environmental pollution due to production of emissions. One particular type of such emissions is NOx. Environmental legislation restricts the amount of NOx that can be emitted by vehicles. In order to comply with this legislation, efforts have been directed at reducing the amount of NOx emissions. One method of emission reduction is directed to reducing the amount of NOx emissions produced during the process of combustion in engines. This method generally involves redesigning engines to optimize the combustion of fuel. This approach has resulted in the reduction of NOx over the years; however, it is often expensive. Further, engines can be tuned to emit less NOx emissions, but this is usually at the expense of increased fuel consumption. Another method is directed to using urea based selective catalytic reduction (SCR) for reducing NOx emissions. In this method, a solution of ammonia or urea contacts the exhaust stream of the combustion source to reduce the NOx to nitrogen, over a SCR catalyst, water and carbon dioxide (if urea is used). This method is disadvantageous as ammonia or urea is toxic and is required to be maintained at sufficient levels for NOx reduction during transportation. Further urea may also be unavailable at all areas and may also be expensive.
Accordingly, there is an ongoing need for improving upon systems and methods that provide reductants in hydrocarbon based selective catalytic reduction (HC-SCR) systems for reduced NOx emissions